I am not the biggest admirer of Ikea Death, but Carnage - Dark Recollections is my favourite album in this style. Also dig the Nihilist stuff and early Unleashed. But of the mentioned bands, Merciless is definitive my choice, although they are not 100% Death Metal to my ears.

Dark Recollections or Into The Grave are probably my two fav full lengths of this style. Far too many out there to pick from though._________________"If noise means uncomfortable sound. Then pop is noise to me" - Masami Akita.